Bake the potatoes especially for the maried couple, along with something over-the-top just for them. Have it prepared ahead of time, to be baked, and get a freind to cook them jsut before the reception, along with the rest of the meal. For everyone else, give them something like riced potatoes, or mashed potatoes. Serve up something cheap, but tasty, like roasted or smoked turkey, pre-sliced and staying warm in a chafing dish half filled with broth.
Serve fresh salad instead of cooked veggies to avoid them being overcooked by the warming trays/chafing dishes.
Or, give everyone else home prepared sunch meats, such as roasted turkey, ham, sirloin tri-tip (sliced very thin against the grain), and bread with condiments and salad fixings so that everyone can make their own sadwhiches, leaving you and your imediate family to enjoy the reception.
Remember, this isn't about feeding bunches of people expensive, free-to-them dinners, but rather, it's a special day for the married couple, who should be given the best, and definitely something better than everyone else gets.
Seeeeeeeya; Goodweed of the North